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Assis, Luiz Santiago de. "Estudo do comportamento temporal do lasr C.W. de ND:YAG usando cristais com centros de cor como absorvedores saturáveis." Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/43/43133/tde-27022014-113956/.
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Existe uma família de centros de cor e cristais dopados com íons metálicos que absorvem na região de emissão do laser de neodímio. Dentre estes, os que são laser ativos são normalmente bombeados em um esquema de cavidades colineares. Eles podem também ser usados como absorvedores saturáveis para o chaveamento Q passivo, C.W. Porém, neste caso a absorção máxima intracavidade que pode ser introduzida é limitada de forma a permitir que a ação laser ocorra. Assim, no caso de ser simultaneamente utilizado como absorvedor e meio ativo existe uma limitação do ganho máximo que o meio ativamente bombeado pode alcançar. Usando-se um esquema de cavidades acopladas, estudamos o desempenho dos centros de cor KCl:T1° (1) e LiF: F POT - IND 2 , para gerar chaveamento Q c.w. passivo (Q- switching) e o travamento de modos (mode-locking) com o esquema de cavidades acima mencionada, na região espectral do infravermelho. Em particular estudamos a ação laser simultânea dos centros KCl: Tl° (1) e do laser de Nd:YAG com o esquema de cavidades acopladas citado, onde o centro de cor tinha o papel dual de absorvedor saturável e meio de ganho. Obteve-se uma alta extração do laser de KCl:Tl° (1), atingindo o limite teórico de 40%, no regime Q-switched c.w.pois a única fonte de perdas do laser de bombeio é o absorvedor saturável. Devido ao baixo ganho dos materiais mencionados e a alta intensidade de saturação foram exploradas as propriedades da cavidade com compensação astigmática, que permite uma grande focalização do feixe sobre o cristal, num regime de cavidades acopladas. Além deste esquema, usamos também um método de bombeamento colinear para a obtenção do travamento de modos ativo-passivo no regime C. W. do laser de Nd: YAG 1 usando o LiF: F POT IND 2 como elemento de modulação passiva dos pulsos. Como um absorvedor saturável lento este necessita de cavidades longas para a obtenção deste regime de operação. Os pulsos modulados (ativamente) sofrem um processo de modulação passiva, o que é dado pela mudança do seu perfil de intensidade de gaussiano para exponencial simétrica, caracterizando a mudança do travamento de modos ativo para passivo.In general, tunable lasers are colinearlly pumped by other powerfull lasers. In the particular case of color centers, that cover the near infrared spectral region, there is a shortcoming due to the difficulty of creating high densities of centers to efficiently extract output energy. One possible way to circumvent this problem is to use intracavity pumping, but there is a limiting factor that is the maximum available gain of the pumping laser, that limits the maximum absortion that can be introduced in the pump laser cavity. A coupled cavities scheme is a solution to solve this problem. In this sense, this scheme was studied using a simple theoretical model. Two sets of experiments were performed, using LiF:F2 and KCl:T1°(1) color centers. In the first case, in which the LiF: F-2 centers were used only as saturable absorber, it was demonstrated that the coupled cavity is responsable for the temporal behavior of the main laser, and operation in the Q-switched mode was obtained, wi th pulses of 1 SJ..S duration. In the second case, KCl:Tl° (1) color centers are also laser active and simultaneous laser operation were achieved, in the Q-switched regime. The remarkable fact was that the pumping efficiency was close to the maximum theoretically allowed and the pulse duration was also totally dependent on the control cavi ty. In both cases, the pulse time duration was in good agreement with the theoretical predictions. The mode-locking regime in these scheme was also studied, using LiF: F-2 color centers, that has a decay time much longer than the cavity round trip time. By the reducing gain a partial modulation in the couple cavity scheme, we only observed a partial modulation of the laser power, indicating that other effects prevent the full modulation. In these case, the effective absortion used was 0,6 % .In order to explore the role of the saturable absorbers in the mode-locking regime, a active modulator was used to start and sustain the regime, besides the presence of the crystal inside the cavity. We clearly observed a change in the shape of the pulses from gaussian to hyperbolic secant squared that is a characteristic of the passivily mode-locked system. In the optimum case the pulse duration was reduced by a factor of 2,4.
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Oluyombo, Olubukola. "Investigation of the antimicrobial properties of the R-type pyocins of Pseudomonas aeruginosa and the role of lasR in their expression." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/38659/.
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Pseudomonas aeruginosa is an opportunistic pathogen responsible for a number of different human infections, and is the leading cause of mortality in cystic fibrosis (CF) patients. P. aeruginosa infections are difficult to treat due to a number of antibiotic resistance mechanisms and its propensity to form multicellular biofilms. It also uses a complex quorum sensing (QS) signalling mechanism to regulate virulence, but mutants in a key QS regulator (LasR) are often prevalent in CF clinical strains. Different strains of P. aeruginosa compete to dominate infections and one way they achieve this is to produce chromosomally encoded bacteriocins, called pyocins. The major classes of pyocins are the soluble (S-types) and the tailocins (R- and F-types). This study investigated the distribution of six S-type and three major groups of R-type pyocins in CF clinical isolates and their roles during strain interactions. Competition assays between strain pairs in both planktonic and biofilm modes of growth were performed between clinical strains and corresponding R-pyocin deletion mutants. Each clinical strain produced one R-pyocin but the distribution of S-pyocins was random. R-pyocins were central to strain dominance as evidenced by the reversal of competitive advantage in null-R-pyocin mutants both in planktonic and biofilm states. R-pyocins also demonstrated novel anti-biofilm activities. Genomic analysis of the most competitive strain (A026) showed that it is a lasR mutant, phylogenetically related to Liverpool Epidemic Strains (LES). Promoter fusion assays to study R-pyocin gene expression showed an increase in the expression of R-pyocin genes in a lasR mutant of PAO1 compared to the wild type. This LasR-linked pyocin expression was RecA-independent. Overall these findings establish the crucial role of R pyocins in P. aeruginosa strain competition and a link between QS and R-pyocins.
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Utpatel, Christian [Verfasser], and Wolfgang [Akademischer Betreuer] Streit. "RNA-seq based identification and biochemical characterization of the Pseudomonas Aeruginosa LasR and Quorum Sensing anti-activator PA2226 / Christian Utpatel ; Betreuer: Wolfgang Streit." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2020. http://d-nb.info/1208394924/34.
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Goh, Wai Kean Chemistry Faculty of Science UNSW. "Novel antagonists of bacterial signaling pathways." Publisher:University of New South Wales. Chemistry, 2008. http://handle.unsw.edu.au/1959.4/41458.
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Traditional bacterial disease therapies utilize compounds that ultimately kill the target bacteria but it exerts a strong selective pressure on the bacteria to develop multi-drug resistance mutants. The increasing occurrence of resistance in common pathogens has highlighted the need to identify new anti-microbials that target the control of bacterial pathogenicity in a non-extermination manner to reduce the incidence of bacteria resistance. One new strategy exploits the discrete signaling molecules that regulate the various bacterial signaling pathways, which are responsible for the expression of pathogenicity traits. Halogenated furanones (fimbrolides) from the marine red alga, Delisea pulchra have been shown to interfere with the key signaling pathway present in Gram-negative bacteria by competitively displacing the cognate signaling molecule from the transcription protein. This project focused on the design and synthesis of 1,5-dihydropyrrol-2-ones, a new class of fimbrolide derivatives capable of displaying strong antagonistic properties of the fimbrolides. Primary synthetic methodologies examined include the halolactamization of allenamides and the direct lactone-lactam transformation. No doubt, both methodologies yielded the lactam ring, the former failed to introduce the crucial C-5 bromomethylene group essential for bioactivity. A facile high yielding two-step lactone-lactam transformation method was developed and using this method, a wide range of substituted 5-bromomethyl- and 5-dibromomethylene-1,5-dihydropyrrol-2-ones were synthesized. Furthermore, a new class of tricyclic crown-ether type compounds with no literature precedent were discovered. To vary the diversity of the compounds, a related class of compounds, 5,6-dihydroindol-2-ones, were examined. A general versatile method for the synthesis of 7-substituted 5,6-dihydroindol-2-ones was developed. The synthetic strategy proceeds via the established Suzuki-Miyaura cross-coupling reaction of halogenated dihydroindol-2-ones with arylboronic acids/esters. The Suzuki methodology was found to be reliable in furnishing a wide range of 7-substituted products in high yields. A preliminary molecular modeling approach was used to assist in the design of new anti-microbials via the ligand-docking analyses of the TraR and LasR protein. A positive correlation was observed between the docking scores and biological activity and the methodology was further developed into an initial screening tool to filter potential active and non-active compounds. The newly synthesized compounds were analysed for their efficacy in reducing the expression of the Green Fluorescent Protein (GFP) in the presence of natural AHL signaling molecules in an AHL-monitor strain, indicative of the inhibition of bacterial phenotype expression. The dihydropyrrol-2-one class of compounds showed significant biological activity and this highlighted their potential for further development.
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Choi, Ji Yeon. "Ecriture par Laser de fonctionnalités optiques : éléments diffractifs et ONL." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2010. http://tel.archives-ouvertes.fr/tel-00583861.
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A la suite de la première démonstration de l'écriture de guide d'onde au sein de verres en 1996 par laser femtoseconde, l'écriture direct par Laser Femtoseconde (Femtoseconde Direct Laser Writing - FLDW) est apparu comme une technique souple pour la fabrication de structure photonique en trois dimensions au sein de matériaux pour l'optique. La thèse a porté sur l'inscription par laser femtoseconde de fonctionnalités optiques au sein de verres. Des éléments diffractifs par modification de l'indice de réfraction et des structures présentant des propriétés de luminescence ou d'optique non linéaire d'ordre deux ont pu être obtenus au sein de matériaux vitreux et étudiés.
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Park, Sukjoon. "Comparative analysis of Pseudomonas aeruginosa LasA and LasD /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487942476405085.
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Mogedas, Vegara Alfonso. "Tratamiento de las leucoplasias orales mediante el laser de dióxido de carbono." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/393916.
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Les leucoplàsies orals són les lesions premalignes més freqüents de la cavitat oral. La possibilitat de degeneració d'aquestes lesions a un carcinoma escamós (taxa de supervivència estimada del 30 al 40% als 5 anys), fa necessari trobar un tractament que sigui capaç de prevenir aquesta transformació maligna alhora de tenir mínims efectes secundaris.
Es presenta una tesi doctoral per compendi d'articles. Els resultats es van publicar al Journal of cranio-Maxillo-Facial Surgery (IF 2,933 en 2014). S'incorpora una revisió sistemàtica sobre el tractament de les leucoplàsies orals mitjançant el làser de diòxid de carboni i un altre article versa sobre l'experiència del Servei de Cirurgia Oral i Maxil·lofacial de l'Hospital Universitari Vall d'Hebron en una mostra de 65 pacients.
D'acord amb la revisió sistemàtica es pot concloure que el tractament de les lesions leucoplasiques mitjançant el làser de CO2 és una tècnica fiable, reproduïble i associada a una molt baixa taxa de complicacions (0-13,8%), amb unes taxes de recurrència i de transformació maligna que oscil·len entre el 3,1% i el 40,7% i del 0% al 15,4% respectivament. Encara que alguns autors han aportat alguns possibles factors relacionats amb les taxes de recurrència i de transformació maligna com: l'alt grau de displàsia, les eritroleucoplasias, l'hàbit de fumar, el consum d'alcohol, les leucoplasies orals no homogènies o múltiples, les lesions de 4 o més centímetres i l'antecedent de carcinoma oral de cèl·lules escamoses; en la majoria de sèries no hi ha un consens sobre la seva rellevància. Pel que fa a la nostra mostra podem concloure que les taxes de recurrència i de transformació maligna va ser del 33,8% i del 15,4% respectivament. A més la localització de les lesions a la geniva en comparació a les trobades en la llengua es va objectivar com un factor de risc en els pacients que van presentar recidives (2,84 [1,07-7,54]). Es va apreciar una tendència entre els pacients que presentaven antecedent de carcinoma oral de cèl·lules escamoses i el risc de desenvolupar una transformació maligna (2,25 [0,62-8,10]). Les complicacions associades al procés van ser 5 (7,7%).Las leucoplasias orales son las lesiones premalignas más frecuentes de la cavidad oral. La posibilidad de degeneración de estas lesiones a un carcinoma escamoso, cuya tasa de supervivencia se estima del 30 al 40 % a los 5 años, hace necesario encontrar un tratamiento que sea capaz de prevenir esta transformación maligna a la vez de tener mínimos efectos secundarios. Se presenta una tesis doctoral por compendio de artículos cuyos resultados se publicaron en el Journal of Cranio-Maxillo-Facial Surgery( IF 2,933 en 2014). Se incorpora una revisión sistemática sobre el tratamiento de las leucoplasias orales mediante el laser de dióxido de carbono y otro artículo versa sobre la experiencia del Servicio de Cirugía Oral y Maxilofacial del Hospital Universitario Vall D´Hebron en una muestra de 65 pacientes. De acuerdo con la revisión sistemática se puede concluir que el tratamiento de las lesiones leucoplásicas mediante el láser de CO2 es una técnica fiable, reproducible y asociada a una muy baja tasa de complicaciones (0-13,8%), con unas tasas de recurrencia y de transformación maligna que oscilan entre el 3,1% y el 40,7% y del 0% al 15,4% respectivamente. Aunque algunos autores han aportado algunos posibles factores relacionados con las tasas de recurrencia y de transformación maligna como : el alto grado de displasia, las eritroleucoplasias, el hábito de fumar, el consumo de alcohol, las leucoplasias orales no homogéneas o múltiples, las lesiones de 4 o más centímetros y el antecedente de carcinoma oral de células escamosas ; en la mayoría de series no existe un consenso sobre su relevancia. Con respecto a nuestra muestra podemos concluir que las tasas de recurrencia y de transformación maligna fue del 33,8% y del 15,4% respectivamente. Además la localización de las lesiones en la encía en comparación a las encontradas en la lengua se objetivó como un factor de riesgo en los pacientes que presentaron recidivas ( 2,84 [1,07-7,54] ). Se apreció una tendencia entre los pacientes que presentaban antecedente de carcinoma oral de células escamosas y el riesgo de desarrollar una transformación maligna ( 2,25 [0,62-8,10] ). Las complicaciones asociadas al proceso fueron 5 (7,7%).
Oral leukoplakia are the most common premalignant lesions of the oral cavity. The possibility of degeneration of these lesions to squamous cell carcinoma (survival rate at 5 years 30-50%), implies the need to find a treatment to prevent this malignant transformation and at the same time with minimal side effects. A doctoral thesis by compendium of two articles which results were published in the Journal of Cranio-Maxillo-Facial Surgery (IF 2,933 in 2014) is presented. A systematic review on the treatment of oral leukoplakia with the carbon dioxide laser and the experience of the Department of Oral and Maxillofacial Surgery Vall d'Hebron University Hospital in a sample of 65 patients is presented. According to the systematic review can be concluded that the treatment of oral leukoplakia by the CO2 laser is a reliable, reproducible technique associated with a very low complication rate (0 to 13.8%). The rates of recurrence and malignant transformation range between 3.1% and 40.7% and 0% to 15.4% respectively. Although some authors have provided some possible factors related to rates of recurrence and malignant transformation as the high degree of dysplasia, eritroleukoplakia, smoking, alcohol consumption, non-homogeneous or multiple oral leukoplakia, injuries of 4 or more centimeters and the history of oral squamous cell carcinoma; in most series there is no consensus about its relevance. Regarding our sample we can conclude that the rates of recurrence and malignant transformation was 33.8% and 15.4% respectively. In addition, the location of lesions in the gums compared to those found in the tongue was observed as a risk factor in patients who had recurrences (2.84 [1.07 to 7.54]). A trend among patients with a history of oral squamous cell carcinoma and the risk of developing malignant transformation (2.25 [0.62 to 8.10]) was observed. Complications associated with the process were 5 (7.7%).
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Last, Philipp [Verfasser], Lars [Akademischer Betreuer] [Gutachter] Linsen, Martin [Gutachter] Hering-Bertram, and Andreas [Gutachter] Birk. "Analysis of Automatic Identification System Data for Maritime Safety / Philipp Last ; Gutachter: Lars Linsen, Martin Hering-Bertram, Andreas Birk ; Betreuer: Lars Linsen." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2017. http://d-nb.info/1124681051/34.
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Wazen, Paul. "Laser NH moyen-infrarouge continu pompe optiquement par lase CO laser et amplificateur de puissance de type Raman, laser à inversion de population accordable en fréquence par effet stark /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376106932.
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König, Kristian Lars [Verfasser], Wilfried [Akademischer Betreuer] Nörtershäuser, and Thorsten [Akademischer Betreuer] Kröll. "Laser-Based High-Voltage Metrology with ppm Accuracy / Kristian Lars König ; Wilfried Nörtershäuser, Thorsten Kröll." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2019. http://d-nb.info/1178672670/34.
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Oliveira, Antonio Cesar de. "Medida de parametros biomecânicos do olho com laser de baixa coerência." Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-27072009-143932/.
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Neste trabalho desenvolvemos um novo método para análise biométrica do olho. Essa análise se compõe de medidas dos parâmetros biomecânicos, ou seja, espessura da córnea, distancia entre a córnea e o cristalino, espessura do cristalino, e distancia entre o cristalino e a retina. Este novo método funciona utilizando o princípio da interferometria com laser de baixa coerência. O conhecimento desses parâmetros e de suma importância para o fornecimento de dados necessários para o implante de lentes intra-oculares, em casos de catarata. Alem disso, eles permitem diagnosticar patologias clinicamente caracterizadas por suas alterações. O instrumento convencionalmente utilizado para essas medidas e o biômetro ultra-sônico. Embora esses biômetros sejam práticos e eficientes, a resolução por análise ultra-sônica esta limitada ao fato do tecido ocular não fornecer ecos satisfatórios em freqüências muito acima de 10 MHz. Uma limitação na resposta de freqüência determina uma subseqüente limitação na precisão de medida, já que esta será tanto maior quanta maior a freqüência. Uma variedade de técnicas diferentes tem sido experimentada nos últimos dez anos visando estabelecer um método mais preciso. Entretanto, várias das alternativas existentes têm sido rejeitadas devido à complexidade operacional e altos custos. A técnica interferométrica, entretanto, reúne alta resolução, simplicidade operacional e baixo custo. Isso pode ser constatado pelos resultados obtidos, os quais revela um enorme potencial aplicativo para futuros trabalhos de pesquisa ou mesmo de diagnose.In this work we have developed a new method for biometric analysis of the eye. This analysis consists of measurements of biomechanical parameters, like thickness of the cornea, distance between the cornea and the crystalline lens, thickness of the crystalline lens and distance between the crystalline lens and the retina. In this new method we use the interferometric principle with a low coherence laser. The knowledge of these parameters is very important in order to supply the necessary data for the implant of intraocular lenes, in the cases of cataract. Besides of allow the diagnosis of the pathologies, which are characterized by their changes. The instrument used in the measurements is an ultrasonic biometer. However the resolution of this instrument is limited by the ocular tissue, which does not allow satisfactory echos in frequencies above 10 MHz. A variety of the techniques have been used in the last ten years in the order to establish a more accurate method. However most of the existing alternatives have been rejected due to operational complexity and high cost. The interferometric technique unites high resolution, operational simplicity and low cost. This can be concluded by the results obtained in this work, which demonstrate the great potentiality of the method for future in academic research or clinical diagnosis.
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Kurachi, Cristina. "Estudo comparativo do laser, do LED azul e da lâmpada convencional no processo de polimerização da resina composta dental." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-09102007-095737/.
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A restauração de resina composta dental possui grande aplicação clínica. A polimerização da resina composta é feita através de um processo de fotoativação, que influenciará diretamente as propriedades finais do material restaurador. O estudo e o desenvolvimento das técnicas e dos dispositivos de fotopolimerização das resinas são fatores de grande relevância para melhorar a eficiência do uso da resina composta na Odontologia. Neste trabalho foram avaliadas três fontes de luz, laser de argônio e diodo emissor de luz azul (LED), em comparação com uma lâmpada de fotopolimerização convencional. Através do estabelecimento do diagrama PTT (Potência- Tempo-Temperatura), foram estabelecidos parâmetros seguros de utilização do laser de argônio, para evitar danos térmicos irreversíveis ao tecido pulpar. Na avaliação da dureza, em função da profundidade de penetração da luz no material, foram estabelecidos os parâmetros de operação do laser de argônio para a obtenção de valores de dureza semelhantes ou melhores aos obtidos com a lâmpada convencional. A microinfiltração, em restaurações classe V polimerizadas com o laser e a lâmpada convencional, não apresentou diferença estatisticamente significante quando comparadas às duas fontes de luz investigadas. A elaboração dos dispositivos à base de LEDs, assim como o estudo da dureza da resina composta curada, possibilitou uma análise do processo de cura e a determinação de parâmetros corretos de utilização dos arranjos de LEDs estudados. Nosso estudo termina com a proposta de um dispositivo alternativo para a fotoativação das resinas compostas.The restorations based on composite resin have great application in modem dentistry. The composite polymerization is obtained by a photoactivation process. The final properties of materials are connected with the cure process. The development of photopolymerization procedures and devices is important to improve the cure efficiency and its quality. In this work, two light sources, argon laser and blue light-emitting diodes (LEDs), were studied and compared to a conventional cure lamp. In the PTT (Power-Time-Temperature) diagram it were established safe working parameters to argon laser application, in order to avoid pulpal damage. The microhardness was used to quantify mechanical properties. The observation of VHN as a function of the depth in the material, allowed us to determine the operational parameters where argon laser produces similar properties compared with the conventional lamp. The microleakage observed in class V restorations cured by laser or conventional lamp was investigated and the result did not show statistical difference when the two light sources were compared. Using the devices based on LEDs it was possible to study the cure process and establish the operational parameters when this alternative light source is considered for use in composite resin cure.
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Meyer, Lars Eckehard [Verfasser]. "In vivo Untersuchung menschlicher Haut mit der fluoreszierenden Methode der konfokalen Laser-Scan-Mikroskopie / Lars Eckehard Meyer." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2008. http://d-nb.info/1022866265/34.
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Lash, Catherine Eileen. "Depositional environment and taphonomy of marine vertebrate biofacies in the lower Cretaceous (Albian) thermopolis shale, South-Central Montana." Thesis, Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/lash/LashC1211.pdf.
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In south-central Montana, west of the Pryor Mountain Range, the Lower Cretaceous Thermopolis Formation contains an unusual abundance of marine vertebrate fossils which comprises the majority of the coarse-grained material in an otherwise fine-grained, marine deposit. The fossil zone lacks invertebrates and contains predominantly marine vertebrate skeletal, tooth, and coprolitic material, including; plesiosaur, marine crocodile, shark, freshwater turtle, ray, saw fish, and boney fish. Four lithofacies associations (depositional packages) represent fluctuations of relative sea level within the Western Interior Cretaceous Seaway during Albian time and correspond to the four designated members of the Thermopolis Formation ('rusty beds", Lower Thermopolis, Sandy, and Upper Thermopolis Members). Deposition of the Thermopolis Formation in south-central Montana occurred within a persistent marine basin even during the lowstand event. Two distinct marine vertebrate bioclastic assemblages occur near the middle of the Thermopolis Formation, at the base of the Upper Thermopolis Member, within a 5.6 m thick zone deposited above a the lowstand event. The first fossil assemblage consists of relatively large, isolated and articulated skeletal elements that are generally dispersed throughout the fossil zone within a structureless claystone/mudstone matrix. This assemblage records a low energy, offshore environment (condensed section) with skeletal accumulation primarily driven by suspension settling of biological components and represents an autochthonous to parautochthonous assemblage. The second fossil assemblage consists of relatively small, fragmented bioclasts that are highly concentrated within very thin, cross-laminated litharenite and sandy volcaniclastic ash lenses. These lenses represent high energy event bed deposition resulting from storm-induced flows that entrained and transported previously accumulated fossil material from a nearshore to an offshore environment and represent an allochthonous assemblage. The coarse-grained bioclasts of the second assemblage are transported and therefore do not represent a correlative transgressive lag as previously thought. The second fossil assemblage occurs within the base of the marine vertebrate fossil zone and is surrounded by the first fossil assemblage; both fossil assemblages are time-averaged and occur within a condensed section. Therefore, syndeposition of these two fossil assemblages occurred within the same offshore depositional environment and represent only a change in depositional energy, not a change in overall depositional setting.
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Gouveia, Fahim. "Projeto de um transceptor óptico para comunicação digital em espaço livre." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-04072007-133531/.
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Os sistemas de comunicação óptica por espaço livre, comumente denominados sistemas FSO (Free Space Optics), servem para estabelecer enlaces de comunicação do tipo wireless, ponto-a-ponto, a uma elevada taxa de dados e com alcances que podem variar de algumas centenas de metros a alguns quilômetros. O interesse pela tecnologia FSO tem sido estimulado pela necessidade de se fornecer soluções complementares às tradicionais (e.g. fibra óptica e RF) visando a atender à crescente demanda por conexões de banda larga. Algumas de suas aplicações mais importantes são a conexão de redes locais de computadores, a conexão de estações rádio base de telefonia móvel às centrais e o acesso de última milha. Embora a tecnologia FSO venha sendo empregada em pequena escala no Brasil, vislumbra-se o potencial de maior aplicação desta tecnologia em um futuro próximo, razão pela qual se propõe este estudo, focado no projeto de sistemas FSO. A principal contribuição deste trabalho é demonstrar uma possível solução para a realização de um enlace óptico operando em espaço livre, destinado a conectar duas redes locais de computadores Ethernet Rápida (100 Mbps). As seguintes atividades foram desenvolvidas: estudo das questões mais relevantes pertinentes ao projeto de sistemas FSO; projeto, construção e caracterização eletro-óptica de circuitos; montagem e demonstração do funcionamento de uma versão de testes do sistema, realizadas em laboratório; estudo de características associadas à transferência de radiação óptica de transmissor para receptor, envolvendo o balanço de potência para estimativa do alcance do enlace, sob condições atmosféricas ideais. Como resultado, obtivemos um sistema de comunicação do tipo full-duplex, operando no comprimento de onda de 850 nm em formato de modulação OOK, a uma taxa de dados efetiva de 125 Mbps. Com base na experiência obtida, melhoras ao sistema são sugeridas no final do trabalho.Free space optical communication systems (FSO systems) provide wireless, point-to-point communication links at high data rates, at maximum distances ranging from hundreds of meters to several kilometers. The growing interest in FSO technology arises from the necessity of providing complementary and alternative solutions to those already adopted (eg. fiber optics and RF), aiming to satisfy the increasing demand for broadband connections. Some of its most important applications are connecting local area networks (LANs), backhauling wireless networks and providing last mile access. Although today FSO is not widely adopted in Brazil, the technology has the potential for being adopted in a greater scale in the near future, which is the reason we propose a study focused on issues related to the design of FSO systems. This work\'s main contribution is to demonstrate a possible solution for the construction of a FSO system intended to connect two Fast Ethernet LANs (100 Mbps). For this purpose, the following activities were developed: study of the main aspects related to FSO system design; design, construction and electrooptical characterization of circuits; mounting and demonstration, in the lab, of a test version of the system; study of characteristics related to radiation transfer from transmitter to receiver, involving the use of the link power budget for an estimation of the maximum distance achievable under ideal atmospheric conditions. The result is a full-duplex communication system that employs the 850 nm wavelength in OOK modulation format, operating at an effective bit rate of 125 Mbps. Based on the knowledge achieved, improvements to the system are suggested at the end of this work.
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Gupta, Shamindra Nath [Verfasser], Lars S. [Akademischer Betreuer] Maier, Lars [Akademischer Betreuer] Klinge, and Martin [Akademischer Betreuer] Oppermann. "Die Effekte der Ca2+-Calmodulin-abhängigen Proteinkinase II (CaMKII) auf die Aktionspotentialmorphologie bei mechanischer Last / Shamindra Nath Gupta. Gutachter: Lars Klinge ; Martin Oppermann ; Martin Oppermann. Betreuer: Lars S. Maier." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://d-nb.info/1044870052/34.
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Díaz, Valdivia José María, and Fernández-Dávila Hernán Víctor Valencia. "Propuesta de implementación del aplicativo Trello para la gestión de las restricciones en Last Planner® System." Master's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2018. http://hdl.handle.net/10757/623852.
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Last Planner es una herramienta muy potente de Lean Construction, pero su utilización no garantiza lograr los objetivos de plazo de un proyecto. Esta investigación se centra en una de las causas por las que los plazos se alargan a pesar de usar Last Planner, o creer hacerlo, y la deficiente gestión de restricciones. Para potenciar este paso tan importante, se ha implementado el uso de Tecnología de la Información y Comunicaciones (TIC ‘s), mediante un aplicativo móvil utilizado desde hace más de 4 años en la industria de telecomunicaciones e informática para el trabajo colaborativo.
La metodología aplicada consistió en analizar un proyecto en curso e implementar un Manual para el uso eficiente del aplicativo, además de unos indicadores de gestión capaces de medir el performance del Porcentaje del Plan Cumplido en una propuesta innovadora y moderna con resultados que se comparten en esta investigación.Last Planner is a very powerful tool of Lean Construction, but its use does not guarantee to achieve the project's deadline objectives. This research focuses on one of the reasons why deadlines are lengthened despite using Last Planner, or believing it and it is the deficient management of restrictions. To enhance this important step, the use of information technology and communications (ICT) has been implemented, using a mobile application used for more than 4 years in the telecommunications and informatics industry for collaborative work. The applied methodology consisted in analyzing an ongoing project and implementing a handbook for the efficient use of the application, as well as management indicators able to measure the performance of the Percent Plan Completed in an innovative and modern proposal shared in this research.
Trabajo de investigación
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Rogers, Kevin Shaun. "Laser desorption/laser ionization mass spectroscopy." Thesis, University of Salford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357037.
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Wu, Jianfeng. "Thulium Doped Microsphere Laser and Fiber Laser." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1369%5F1%5Fm.pdf&type=application/pdf.
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Neto, Jonas Jakutis. "Lasers de Nd:YLF de baixo ganho operando na transição de quase-três níveis e em lasers Raman." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-29042013-100734/.
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Lasers operando nas regiões espectrais do azul e do amarelo-laranja foram recentemente requisitados pelo mercado de aplicações quer para melhorar as tecnologias já conhecidas ou para possibilitar a criação de novas. Isso é devido às propriedades destas regiões espectrais, com o azul trazendo características tais como fótons de alta energia e feixes limitados por difração menores, enquanto a faixa do amarelo-laranja é ainda uma região espectral difícil de se atingir e não foi totalmente acessada ou nem mesmo acessada por fontes de luz laser eficientes. Aplicações dos lasers azuis são encontradas em tecnologias de alta densidade de armazenamento, displays a laser, sistemas LIDAR, pinças ópticas e uma longa série de aplicações que exigem alta precisão. Os lasers amarelo-laranja também têm aplicações importantes, destacando-se aplicações em cirurgia oftalmológica a laser, em displays de cores reais e como estrela guia (excitando linhas de sódio na atmosfera). A investigação de lasers de quase três níveis e laser Raman de Nd:YLF foi realizada neste trabalho. A finalidade é de propor fontes laser de alta potência e eficientes emitindo no azul e no amarelo para suprir as aplicações. Eficiência e potências de saída da ordem de Watt foram demonstradas para um laser de Nd:YLF emitindo em 908 nm assim como no segundo harmônico em 454 nm. Além disso, lasers Raman de Nd:YLF/BaWO4 e Nd:YLF/KGW foram demonstrados atingindo alguns Watts de potência de saída em regime quasi-CW e CW, com boas qualidades de feixe (M2 2) e em oito comprimentos de onda diferentes: 1147 nm, 1163 nm, 1167 nm , 549 nm, 552 nm, 573 nm, 581 nm e nm 583. Por fim, uma luminescência azul originada em alguns cristais Raman, durante a oscilação Stokes, teve sua origem e seus efeitos colaterais para lasers (perdas e calor adicionais) minuciosamente caracterizados.Lasers operating in the blue and yellow-orange spectral regions are sought after by the applications market either to improve well known technologies or to enable new ones. Blue lasers bring features such as high energy photons and smaller diffraction limited beams, while the yellow-orange range is a hard to reach spectral region where there is a considerable shortage of efficient laser light sources. Applications of the blue lasers are found in high density storage technologies, laser displays, LIDAR systems, optical tweezers and a long range of high precision demanding applications. The yellow-orange lasers also have important applications, with highlights in ophthalmologic laser surgery (photocoagulation), in true color displays and as a guide star (exciting sodium lines in the atmosphere). The investigation of Nd:YLF quasi-three level lasers and Nd:YLF Raman lasers was further studied in this work in order to provide high power and efficient blue and yellow lasers sources. Demonstrations of efficient and multi-Watt operation of a 908 nm laser and its respective second harmonic laser at 454 nm are described. Also, Nd:YLF/BaWO4 and Nd:YLF/KGW Raman lasers were demonstrated reaching Watt levels in quasi-CW and CW regime with very good beam qualities (M2 2) at eight different wavelengths: 1147 nm, 1163 nm, 1167 nm, 549 nm, 552 nm, 573 nm, 581 nm and 583 nm. Finally, a blue luminescence originating in some Raman crystals, during Stokes oscillation, has been studied in considerable detail. Its origin and consequences for laser operation (extra loss and heat load) have been identified.
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Chauzat, Corinne. "Études expérimentales de lasers microchips à émission continue mono-fréquence à 553 nm et à 561 nm, de puissance supérieure à 200 mW." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S007.
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Le remplacement des lasers à colorant émettant dans la gamme 550-570 nm, à l'aide de lasers solides, représente un véritable enjeu industriel. Les applications sont multiples tant dans le domaine de la recherche biomédicale que dans celui de la métrologie. Quelques solutions ont été développées à 561 nm et à 553 nm. Néanmoins, elles ne permettent pas de fournir des lasers intégrables parfaitement mono-fréquences émettant en continu un faisceau gaussien, d'une puissance supérieure ou égale à 200 mW. Dans ces travaux, nous proposons une étude théorique et expérimentale de cavités lasers solides monolithiques à base de Nd:YAG pompé par diode, doublé en fréquence en intra-cavité, à l'aide d'un cristal non-linéaire de KTP. Ces cavités, constituées de plusieurs cristaux, sont contactées par adhérence moléculaire. Elles ne contiennent aucune optique de mise en forme des faisceaux et présentent la particularité de comporter un double filtre de Lyot. Nous présentons les résultats obtenus avec des cavités émettant à 561 nm pour des puissances supérieures ou égales à 300 mW. Puis, après une étude statistique et une analyse des résultats de test de ces cavités à long terme (> 6000 heures), nous discutons des problèmes éventuels de fiabilité et nous suggérons des axes d'amélioration. Ayant réussi à faire osciller, pour la première fois, la raie à 1106 nm du Nd:YAG, nous montrons ensuite la faisabilité d'un laser compact mono-fréquence continu à 553 nm, émettant une puissance de 200 mW à 500 mW avec un rendement de conversion pompe/laser visible de l'ordre de 19 %. Pour conclure, nous montrons qu'il est possible, dans des cavités de ce type, de faire osciller des raies Raman issues des raies fondamentales et de les doubler en fréquence en intra-cavité. Nous ouvrons ainsi la porte à toute une famille de lasers solides émettant dans la gamme 540-600 nmReplacement of dye lasers emitting in the range 550-570 nm, using solid state lasers, is a real industrial issue. There are many applications both in the field of biomedical research than in metrology. Some solutions have been developed for 561 nm and 553 nm. However, they do not provide fully integrated lasers emitting single-frequency continuous Gaussian beam with a power equal or up to 200 mW. In this work, we propose a theoretical and experimental study of solid monolithic cavity lasers based on Nd:YAG diode-pumped, frequency-doubled intra-cavity, using a non-linear crystal of KTP. These cavities, consisting of several crystals, are contacted by molecular adhesion. They contain no optical layout of the beams and they have the particularity of including a double Lyot filter. We present the results obtained with those cavities emitting at 561 nm for powers greater than 300 mW. Then, after a statistical study and analysis of test results of these cavities in the long term (> 6000 hours), we discuss about the potential problems of reliability and we suggest areas for improvement. For the first time, we show that the line at 1106 nm of the Nd: YAG can oscillate in this type of cavity. Then we demonstrate the feasibility of a compact single-frequency laser at 553 nm continuously, emitting a power of 200 mW to 500 mW with a conversion efficiency of pump / visible laser of about 19%. Finally, we show that it is possible, in cavities of this type, to oscillate the Raman lines from the lines of the fundamental and doubled frequency in intra-cavity. We open the door to a whole family of solid state lasers emitting in the range of 540-600 nm
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Almeida, Ivan Alves de. "Otimização do processo de usinagem de titânio com laser pulsado de neodímio." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-13062008-162120/.
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Um requisito do processo de manufatura é a necessidade de se obter peças processadas, caracterizadas pela boa qualidade de acabamento superficial, baixa rugosidade e a conservação de suas propriedades metalúrgicas. Essas condições motivaram o desenvolvimento deste estudo, no qual selecionou-se o processamento de materiais a laser para o corte do titânio, unindo uma tecnologia a um metal de recente aplicação. Além disso, a versatilidade e as vantagens, como também a tendência global do setor industrial, tornaram-se fatores preponderantes na utilização do laser como ferramenta de usinagem. Neste presente trabalho foram investigados os efeitos da usinagem por laser pulsado de Nd:YAG sobre a qualidade, como também a formação de fases na superfície de corte e analisados pela aplicação do planejamento experimental. Para isso, chapas de titânio comercialmente puro (grau 2) e da liga Ti-6Al-4V (grau 5), com espessuras de 0,5 e 1,0 milímetros, foram empregadas na realização dos ensaios sob ação do laser. As amostras obtidas foram analisadas por microscopia ótica (MO), microscopia eletrônica por varredura (MEV), ensaios de microdureza e inspeção superficial da rugosidade. Capturaram-se digitalmente as imagens do material ressolidificado, aderido na superfície de corte para determinação da formação de rebarbas. Com base nestes dados construíram-se arranjos fatoriais, por meio da metodologia de planejamento experimental (DOE), a fim de avaliar o grau de influência dos parâmetros e suas possíveis interações e assim averiguar sua significância estatística. Verificou-se um endurecimento superficial na região do corte a laser com nitrogênio, em virtude da formação de nitretos (TiN) sob uma fina camada da zona de ressolidificação. Apesar da complexidade das interações entre os diversos parâmetros envolvidos no processamento a laser, os resultados corroboram que a otimização do processo de corte a laser do titânio pode ser factível.The main goal of this work was to establish the requirements for laser processed parts to satisfy uniform surface finish, low roughness and preservation of the mechanical and functional properties of the parts. Lasers became a versatile machining tool that satisfies the modern trends in material processing. In this study, the cutting quality factors of sheets of pure titanium and its alloys, by pulsed Nd:Yag laser, were investigated according to the Design and Analysis of Experiments. Laser pulse energy, laser pulse length, pressure of the protective/reactive gas, cutting speed, were considered the key laser parameter processing factors. In this Design, a factorial arrangement, regarding several combinations of these different processing factors, was performed and the influence of each one was also taken into consideration. The cutting process was performed on commercially pure titanium (grade 2) and the alloy Ti-6Al-4V (grade 5) sheets. The obtained samples were analyzed through optical microscopy in order to determine the edge roughness formations. The samples were also analyzed by scanning electron microscopy and submitted to micro hardness tests and surface roughness inspections. An increase on the surface hardness on the cut region and the formation of nitrogen precipitates under a thin layer of a melted zone were verified. In spite of the complexity of the interactions between this diversity of parameters, it is possible to optimize the titanium laser cutting.
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Löser, Markus. "Diode-Pumped High-Energy Laser Amplifiers for Ultrashort Laser Pulses The PENELOPE Laser System." Doctoral thesis, Helmholtz-Zentrum Dresden - Rossendorf, 2017. https://tud.qucosa.de/id/qucosa%3A30755.
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The ultrashort chirped pulse amplification (CPA) laser technology opens the path to high intensities of 10^21 W/cm² and above in the laser focus. Such intensities allow laser-matter interaction in the relativistic intensity regime. Direct diode-pumped ultrashort solid-state lasers combine high-energy, high-power and efficient amplification together, which are the main advantages compared to flashlamp-pumped high-energy laser systems based on titanium-doped sapphire. Development within recent years in the field of laser diodes makes them more and more attractive in terms of total costs, compactness and lifetime.
This work is dedicated to the Petawatt, ENergy-Efficient Laser for Optical Plasma Experiments (PENELOPE) project, a fully and directly diode-pumped laser system under development at the Helmholtz–Zentrum Dresden – Rossendorf (HZDR), aiming at 150 fs long pulses with energies of up to 150 J at repetition rates of up to 1 Hz. The focus of this thesis lies on the spectral and width manipulation of the front-end amplifiers, trivalent ytterbium-doped calcium fluoride (Yb3+:CaF2) as gain material as well as the pump source for the final two main amplifiers of the PENELOPE laser system. Here, all crucial design parameters were investigated and a further successful scaling of the laser system to its target values was shown.
Gain narrowing is the dominant process for spectral bandwidth reduction during the amplification at the high-gain front-end amplifiers. Active or passive spectral gain control
filter can be used to counteract this effect. A pulse duration of 121 fs was achieved by using a passive spectral attenuation inside a regenerative amplifier, which corresponds to an improvement by a factor of almost 2 compared to the start of this work. A proof-of-concept experiment showed the capability of the pre-shaping approach. A spectral bandwidth of 20nm was transferred through the first multipass amplifier at a total gain of 300. Finally, the predicted output spectrum calculated by a numerical model of the final amplifier stages was in a good agreement with the experimental results.
The spectroscopic properties of Yb3+:CaF2 matches the constraints for ultrashort laser pulse amplification and direct diode pumping. Pumping close to the zero phonon line at 976nm is preferable compared to 940nm as the pump intensity saturation is significantly lower. A broad gain cross section of up to 50nm is achievable for typical inversion levels. Furthermore, moderate cryogenic temperatures (above 200K) can be used to improve the amplification performance of Yb3+:CaF2. The optical quality of the doped crystals currently available on the market is sufficient to build amplifiers in the hundred joule range.
The designed pump source for the last two amplifiers is based on two side pumping in a double pass configuration. However, this concept requires the necessity of brightness conservation for the installed laser diodes. Therefore, a fully relay imaging setup (4f optical system) along the optical path from the stacks to the gain material including the global beam homogenization was developed in a novel approach.
Beside these major parts the amplifier architecture and relay imaging telescopes as well as temporal intensity contrast (TIC) was investigated. An all reflective concept for the relay imaging amplifiers and telescopes was selected, which results in several advantages especially an achromatic behavior and low B-Integral. The TIC of the front-end was improved, as the pre- and postpulses due to the plane-parallel active-mirror was eliminated by wedging the gain medium.
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Löser, Markus. "Diode-Pumped High-Energy Laser Amplifiers for Ultrashort Laser Pulses The PENELOPE Laser System." Helmholtz-Zentrum Dresden - Rossendorf, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-232322.
Full textAbstract:
The ultrashort chirped pulse amplification (CPA) laser technology opens the path to high intensities of 10^21 W/cm² and above in the laser focus. Such intensities allow laser-matter interaction in the relativistic intensity regime. Direct diode-pumped ultrashort solid-state lasers combine high-energy, high-power and efficient amplification together, which are the main advantages compared to flashlamp-pumped high-energy laser systems based on titanium-doped sapphire. Development within recent years in the field of laser diodes makes them more and more attractive in terms of total costs, compactness and lifetime.
This work is dedicated to the Petawatt, ENergy-Efficient Laser for Optical Plasma Experiments (PENELOPE) project, a fully and directly diode-pumped laser system under development at the Helmholtz–Zentrum Dresden – Rossendorf (HZDR), aiming at 150 fs long pulses with energies of up to 150 J at repetition rates of up to 1 Hz. The focus of this thesis lies on the spectral and width manipulation of the front-end amplifiers, trivalent ytterbium-doped calcium fluoride (Yb3+:CaF2) as gain material as well as the pump source for the final two main amplifiers of the PENELOPE laser system. Here, all crucial design parameters were investigated and a further successful scaling of the laser system to its target values was shown.
Gain narrowing is the dominant process for spectral bandwidth reduction during the amplification at the high-gain front-end amplifiers. Active or passive spectral gain control
filter can be used to counteract this effect. A pulse duration of 121 fs was achieved by using a passive spectral attenuation inside a regenerative amplifier, which corresponds to an improvement by a factor of almost 2 compared to the start of this work. A proof-of-concept experiment showed the capability of the pre-shaping approach. A spectral bandwidth of 20nm was transferred through the first multipass amplifier at a total gain of 300. Finally, the predicted output spectrum calculated by a numerical model of the final amplifier stages was in a good agreement with the experimental results.
The spectroscopic properties of Yb3+:CaF2 matches the constraints for ultrashort laser pulse amplification and direct diode pumping. Pumping close to the zero phonon line at 976nm is preferable compared to 940nm as the pump intensity saturation is significantly lower. A broad gain cross section of up to 50nm is achievable for typical inversion levels. Furthermore, moderate cryogenic temperatures (above 200K) can be used to improve the amplification performance of Yb3+:CaF2. The optical quality of the doped crystals currently available on the market is sufficient to build amplifiers in the hundred joule range.
The designed pump source for the last two amplifiers is based on two side pumping in a double pass configuration. However, this concept requires the necessity of brightness conservation for the installed laser diodes. Therefore, a fully relay imaging setup (4f optical system) along the optical path from the stacks to the gain material including the global beam homogenization was developed in a novel approach.
Beside these major parts the amplifier architecture and relay imaging telescopes as well as temporal intensity contrast (TIC) was investigated. An all reflective concept for the relay imaging amplifiers and telescopes was selected, which results in several advantages especially an achromatic behavior and low B-Integral. The TIC of the front-end was improved, as the pre- and postpulses due to the plane-parallel active-mirror was eliminated by wedging the gain medium.
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Kiehn, G. P. "XUV laser amplication in recombining laser produced plasmas." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379973.
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Romagnani, L. "Laser-plasma investigations employing laser-driven proton probes." Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426587.
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Qiu, Wenqian. "Modelling of laser-plasma in laser microspectral analysis." Thesis, University of Aberdeen, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386302.
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The behaviour of the laser-produced plasma plume plays an important part in understanding and controlling the laser material processing involved in laser microspectral analysis. A multi-dimensional time-dependent model has been developed to simulate the transient material behaviour after an intense laser pulse irradiating a target surface. In this model, the heating and phase transition of the target material have been studied using the heat transfer theory, and the formation and evolution of the plasma plume were modelled by the Euler equations of fluid dynamics, which include the conservation of mass, momentum and energy. The energy absorption in the plasma by inverse Bremsstrahlung was considered, and the interface between the plasma plume and surrounding air was tracked by a fractional volume method. Moreover, the temperature-dependent optical and thermal properties of the target material and the spatial and temporal characteristics of the laser irradiance have been taken into account. The equations in the model were solved numerically by means of a finite-volume based time marching algorithm. Finally, experiments were carried out to support this model. This model is capable of predicting the onset of melting and evaporation, the crater development, the transient temperature distribution in the target, spatial and temporal behaviour of the plasma flow and, finally, the formation and propagation of a shock wave in the surrounding air. The transient spatial distributions of the plasma parameters, i.e., the temperature, density, pressure and velocity are presented in two-dimensional colour contour diagrams as well as the transient temperature profiles in the target. All these outcomes enable the optimisation of the process of laser-material interaction and provide valuable information in interpretation of the recorded spectrum and the consequent quantitative analysis of target composition in laser microspectral analysis.
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Hamidi, Serajeddin. "Filamentation of laser light in laser-produced plasmas." Thesis, University of Essex, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279422.
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Komashko, Aleksey Mikhaylovich. "Laser-material interaction of powerful ultrashort laser pulses /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Lee, Junho. "Semiconductor diode laser with saturable absorber (S-laser)." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0004277.
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Mild, Axel, and Arvid Mild. "Hållbar last mile distribution : Sustainable Last Mile Distribution." Thesis, Uppsala universitet, Industriell teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-418146.
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Syftet med examensarbetet är att utforma en distributionscentrals processer för identifiering, sortering och packning av gods, för att möjliggöra en hållbar last mile-distribution med cykel. Varulogistik i städer är en stor utmaning för att främja en hållbar stadsutveckling. Transporter är nödvändiga för att förse verksamheter och invånare med gods. Samtidigt bidrar dessa transporter till negativa miljöpåverkningar, i form av buller och utsläpp. Kommuner har en central roll i att främja en hållbar utveckling på grund av deras planmonopol och möjligheter att reglera trafiken. Ett sätt att minska tyngre trafik i innerstäder är genom införandet av mindre, energieffektiva distributionsfordon för last mile-leveranser av lättare paket. Studien bygger på en mix av kvalitativa och kvantitativa metoder. Intervjuer med experter inom området, samt studiebesök hos framgångsrika transportföretag har gett en bred kunskap i området. Tillgång till data inom nuvarande processer har dessutom hjälpt forma de två lösningsförslag som slutligen presenteras i studien. Resultatet av studien framkommer i två lösningsförslag, ett nutidsförslag och ett framtidsförslag. Nutidsförslaget innehåller förändringar i såväl nuvarande processer som införandet av nya. Förslagen som presenteras här är mindre resurskrävande att implementera och ses därför vara möjliga att genomföra i dag. Framtidsförslaget presenterar vidare förbättringar som kan tillämpas inom terminalens processer. Dessa förslag är mer resurskrävande. Trots att studien är utförd efter specifika önskemål från uppdragsgivaren täcker den relevanta områden som är av intresse för alla företag som vill implementera en last mile-lösning med hjälp av cykelfordon.
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Berry, Patrick A. "Versatile Chromium-Doped Zinc Selenide Infrared Laser Sources." University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1271776256.
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Vigil, Ricardo. "Laser accelerator." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/44024.
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Approved for public release; distribution is unlimitedIn 1979,W. B. Colson and S. K. Ride proposed a new kind of electron accelerator using a uniform magnetic field in combination with a circularly-polarized laser field. A key concept is to couple the oscillating electric field to the electron’s motion so that acceleration is sustained. This dissertation investigates the performance of the proposed laser accelerator using modern high powered lasers and mag-netic fields that are significantly improved over the values in the original analysis. The relativistic equations of motion for the electron are solved analytically and for the first time numerically for more general results than previously reported. Realistic beam effects are investigated to determine the constraints on initial electron energy, injection angle, and phase to achieve optimal performance. This analysis indicates that the selection of an electron’s initial conditions are not as stringent as previously thought. Simulations indicate a university scale system can achieve electron energy gain of over one GeV in a meter.
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Lee, Soo-Keun. "Laser photocatalysts." Thesis, Robert Gordon University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344019.
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Pexton, Valerie. "Last dance." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1605161601&sid=2&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Mendiola, David Mario. "Laser guitar." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45322.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 24).
Music is constantly evolving, both in the culture and musical theory that dictates its structure, and the technology used to create the actual sound. This thesis explores a direction for development of one of the most proven instruments in musical brainstorming as well as live performance; the guitar. The form and feel has stayed nearly the same since its conception and it is a solid foundation with which to integrate modern technology. The design is to replace the strings with beams of laser that run through a line of beam splitters at each fret, each of which sends a beam onto a photoresistor. By blocking the beam at different frets, the current through the resistors uniquely determines what fret is pressed. The motivation for this development is twofold; firstly, the aesthetic appeal of a brilliantly lit guitar could make this a popular instrument for live shows, and, secondly, the lasers would be more versatile than strings, allowing the player to program frets to be any note. By doing this, the writing process could be enhanced with more options to experiment with, and the performance of difficult compositions could be simplified. This paper begins the design of the instrument and proposes solutions for some possible complications in creating it.
by David Mario Mendiola.
S.B.
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Monson, Paul J. E. "Laser hardfacing." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47187.
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Elkins, Alan P. "Last Castle." Bowling Green State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1242326601.
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Villegas, Megan A. "Last Rites." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1212086186.
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Haponek, Ken. "LAST MONDAY." Wright State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=wright1180997881.
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Chung, S. H. "Gunn laser." Thesis, University of Essex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421149.
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Amescua, Dacasa María Elena. "Sistema Operativo Urbano, Puebla." Thesis, Universidad de las Américas Puebla, 2009. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/amescua_d_me/.
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Sánchez, Portillo Jaqueline. "Proyecto Urbano para la Ciudad de Cuautla,Morelos." Thesis, Universidad de las Américas Puebla, 2010. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/sanchez_p_j/.
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Aguilar, Sotomayor Raúl. "Prototipo de Vivienda Prefabricada y Progresiva." Thesis, Universidad de las Américas Puebla, 2010. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/aguilar_s_r/.
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Peña, Ordoñez Martha Laura. "Estación Ecoturística en el Cañón del Sumidero en Chiapas." Thesis, Universidad de las Américas Puebla, 2010. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/pena_o_ml/.
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Valdespino, Padilla Cinthya Abigail. "Centro Art��stico de la Universidad de las Am��ricas Puebla." Thesis, Universidad de las Am��ricas Puebla, 2011. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/valdespino_p_ca/.
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The fine arts have been present throughout my life by different means, they have been a fundamental part of my personal and professional development. I have witnessed the lack of support and indifference of the Mexican people to the culture and arts. So when entering a career in architecture I decided to develop a project to promote culture and the arts from a different perspective that I always showed, now from the architecture perspective.
As I gained knowledge I realized the great architectural heritage that we Mexicans have, how lucky we are, and how little we value and in most cases it is more appreciated by foreigners than by ourselves. I am a proud Mexican and that is why I am interested in rescuing our ancestor��s heritage. That is where the idea for this project flourished.
This is due to two problems, that can be solved by rescueing an architectural monument that has historical value, "the haciendas", elements of economic and social importance in the history of our country. Our case is reflected through the exhacienda San Jose Zavaleta, this property is recovered for reuse and is involved in a space dedicated to culture and the arts, which can be promoted by a private institution, in our case the Universidad de las Americas Puebla, same space lacking the necessary characteristics for this genre.(cont.) This is how you get a project that benefits the Mexican society and its cultural identity, their social reality and its surroundings immediately. This is a project that addresses real problems, making it a viable and original project, which promotes the conservation, restoration and reuse of a building with heritage value that contributes significantly to Mexican society, culture and architecture..
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Nájera, Rendón Daniel. "Asia Town + Casa Asia Puebla." Thesis, Universidad de las Américas Puebla, 2011. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/najera_r_d/.
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Ramírez, Stege Alexandra. "The Ownable City: Urban Strategies That Promote Identity." Thesis, Universidad de las Américas Puebla, 2013. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/ramirez_s_a/.
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Sáenz, de Miera Cuatlayol Fernando. "Casa de Retiro para el Adulto Mayor "Nuevo Encuentro" ubicada en San Miguel de Allende, Guanajuato." Thesis, Universidad de las Américas Puebla, 2012. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/saenz_d_f/.
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En esta tesis se contiene la propuesta de una Casa de Retiro para el adulto mayor en San Miguel de Allende, Guanajuato.
Para la realización de este proyecto se tomaron en cuenta aspectos demográficos, sociales, culturales, climatológicos, así como normas, leyes y derechos del adulto mayor.
Se analizaron también algunos casos análogos de la República Mexicana, concluyendo así, qué espacios serían básicos en una Casa de Retiro, qué orientación sería la óptima para cada uno de ellos, qué factores ambientales deberían estar presentes, con qué equipamiento debería contar etc.
Se propusieron también espacios complementarios, así como espacios híbridos y anexos, éstos últimos teniendo un valor adicional ya que funcionarían como espacios rentables, dándole sustento económico a la Casa de Retiro.
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Serapio, Lara Génesis Raquel. "Centro de Diseño Textil y Moda." Thesis, Universidad de las Américas Puebla, 2012. http://catarina.udlap.mx/u_dl_a/tales/documentos/lar/serapio_l_gr/.
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